System for cooling the intermediate wall of vehicle engines



1954 P. TORRE 2,696,200

SYSTEM FOR COOLING THE INTERMEDIATE WALL. OF VEHICLE ENGINES Filed May 2, 1952 [Alva/woe United States Patent SYSTEM FOR CDOLHYG THE INTERMEDIATE WALL OF VEHICLE ENGINES Pier Luigi Torre, Milan, Italy Application May 2, 1952, Serial No. 285,776

Claims priority, application Italy May 2, 1951 1 Claim. c1. 123--41.16)

Amongst the types of two cycle engines for auto vehicles and in particular for motor cycles, offering good conditions for scavenging, are the so called divided cylinder motors, having two side by side parallel cylinders, closed by a common head.

The adoption of such a construction, enjoying some advantages especially in What concerns the scavenging characteristics, meets with some drawbacks, first of all the difficulty of cooling conveniently in a simple way the intermediate wall resulting between the two cylinders. This drawback greatly hinders the adoption of said divided cylinder engines, at least in the field of high power efliciency.

The present invention has as an object a cooling systern for said wall, that ensures a good cooling of it Without requiring, as other known similar systems do, a noticeable increase of thickness of said wall which would originate drawbacks in the kinematics of the system.

More specifically, according to the system being the object of the invention, in the intermediate wall between the cylinders, that are to be cooled, channels and cavities are provided, which are then filled with sodium, which, by melting and evaporating under the action of heat, remarkably betters the carrying ofi" of the heat from the hottest points.

The accompanying drawing diagrammatically illustrates by way of example the block of a divided cylinder engine provided with the system being the object of the present mvention.

Fig. 1 illustrates a plan view of a motorcycle divided cylinder engine in whose intermediate wall are provided the cavities necessary for applying the system in question.

Fig. 2 is a section through line AA of the motor shown in Fig. 1.

As is evident from the drawing, the engine illustrated comprises two cylinders 1 and 2, that in the case illustrated have parallel axes, and are separated from each other by a wall 3 being a part of the casting in which are provided two conduits 4 and 5 that in the example illustrated are parallel to the cylinder axes and are con- "ice nected between them by a plurality of cross channels 6 that prolongate themselves until they issue into two larger expansion chambers 7 and 8.

Channels 4 and 5, as well as cavities 7 and 8 are hermetically closed by plugs 99, 1010, respectively. Conduits 4 and 5, as well as cross conduits 6 are filled, before closing them by means of plugs 9, with solid sodium which, at the normal temperature remains in this physical state, but, when the engine in working on account of the great heating of wall 3, at first melts and then commences to boil absorbing a noticeable quantity of heat and expanding itself into chambers 7 and 8, thus the heat absorbed by it is transmitted to the side, fin carrying walls 11 and 12 of the engine block. In this way, an effective cooling of wall 3 is obtained, even under a prolonged working of the engine. And as, when the engine stops and cools off, the sodium again solidifies, and remains therefore in the closed cavities provided in said wall 3, this cooling system is ready to function at all times the engine is started up.

To all that are expert in this branch of technique it will be evident the technical advantages of simplicity and safety possessed by the cooling system are the object of the present invention.

Of course, the forms, the dimensions of the channels and cavities provided in the partition between the cylinders, the number of such partitions in each engine and all the constructional details may variate according to necessity, without going out of the realm of the present invention.

What I claim is:

An air cooled cylinder construction for an internal combustion engine comprising a block having a pair of parallel cylinder bores with a wall between them, said wall having a plurality of elongated ducts extending parallel to the cylinders between the two cylinders, said block having a pair of expansion chambers provided in the upper portion thereof and extending partly into said wall between the cylinders, said block having a plurality of channels extending transversely of the elongated ducts and spaced axially of said ducts providing communication between the upper portions of the elongated ducts and communication between said ducts and the expansion chambers, a mass of material fusible and vaporizable at the operating temperature of the engine, in said ducts, channels and expansion chambers, and fins on the exterior of said block.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,763,082 Bauer et a1 June 10, 1930 2,062,391 Brown 2 Dec. 1, 1936 2,338,691 Tucker Jan. 4, 1944 2,554,921 Pobjoy May 29, 1951 

